Mold for constructing concrete tunnels.



G. R. ABBOTT.

MOLD FOR CONSTRUCTING CONCRETE TUNNELS.

' APPLICATION man mw a, 1914.

Patented Am. 27, 1915.

2 SHEETS-SHEET l.

r THE NaRR/S PETERS Ca. PHOTO-urna, WASHINGTON, DA f:A

G. R. ABBOTT.

MOLD FOR coNsTRucTmG CONCRETE TUNNELS.

APFLiCATION FILED MAY 8| 1914.

PD. M. 2 .ILT ,E MISE 2M um .AM dS e2 b n ou il na D1 Wre f @unam (ami/lineman Tui NoRRls PETERS CO.. FHOTD-LITHO., WASHINGID' GI-IEEN E. ABBGTT, OF BALTIMORE, MARYLAND.

MOLD FOR CONSTRUCTING- CONCRETE TUNNELS.

mamas.

lSpecification of Letters Patent.

Patented Apr. 27, 1915.

Application filed May 8, 1914. Serial No. 837,122.

T0 all Whom t may concern:

Be it known that I, GEBEN R. ABBOTT, a citizen of the United States, residing at Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Molds for Constructing Concrete Tunnels, of which the following is a specification.

This invention relates to collapsible molds or centers for the for ation of tunnels for conduits, sewers, and other earth-covered structures.

@ne object of my invention is to provide an improved construction of a cylindric, or part-cylindric mold of light metal for use in forming concrete or cement earth-covered conduits, whether formed by tunneling or in a ditch and then covered.

The improved mold is illustrated in the accompanying drawing in which,-

Figure l is a cross-sectionV of a conduit, and a mold-section wi .iin the conduitthe single arch-rib' angle-bar at the end of the section being shown. .The base is made of brick and the arch of concrete. Fig. 2 is a top plan of a portion ofmold used in tunneling, and shows the door or Akey that closes the top-opening in the mold. Fig. 3 is a vertical longitudinal section of the partcylindric mold taken on the line 3-3 of Fig. l; this figure shows Vone half of one mold section. Fig. l shows a cross section on line 4 4 of Fig. 8, showing the keyplate that closes the top-opening. Fig. 5 shows the single arch-rib at the top-opening, a nd illustrates the supplemental piece of rib that is added to span across said top-opening. Fig. G is a perspective view of the intersection and joincr of one arch-rib and one straight longitudinal connecting anglebar. Fig. is a view of an end-coupling of one of the turn-buckle rods. Fig. 8 is a view of part of the trap door or key. Fig. 9 shows a detail of one journal bracket, and Fig. 10 is a cross-section of a cylindric mold of a conduit which in this instance is made wholly of concrete, and showing Athe rods used for collapsing the mold.

Referring to the drawing Fig. 1 shows a cross-section of aV cylindric conduit in which the invert, 9, is made of brick restingv on a foundation, 10, of concrete, and the arch, 11, rests on the said brick invert. In forming a conduit ofV this construction I use a part-cylindric mold, 14, which should be made in sections of a length convenient to handle. Tovaii'ord support for the partcylindric mold, I use cross-ties, 12, with undercut beveled ends, 13, which rest on the sloping surface of the brick-work of the invert, 9. The cross-ties at the bottom of the conduit may form a cover', approximately, for two sevenths of the interior. cylindric surface of the conduit, that is, a cover over the brick invert, 9, thereby the part-cylindric mold, Ill, would extend over about five sevenths of said interior surface of the conduit comprising the arch, 11. Two pairs of wood stringers are supported on the crossties, l2. One pair, l5, at the center (Fig. l) serves to support the iron rails, 16, that constitute the car-track; and the other pair of stringers, 17, are traversed by the rollers, 1S, hereinafter described, that serve to move a section of the part-cylindric mold. The said part-cylindric mold is shown in Figs. 1 and 3, and comprises a series of arch-ribs, 19,-each formed of two curved angle-bars; these two bars are placed together in contact side by side and form a T in cross section, so that the outer or conveX curved surface, 20, of the two bars will be flush with each other and constitute the top cross of the T and the outer sheet-metal shell, 24, rests on said part, Q0. The sides of the two curved angle-bars that are in contact, are fastened together by rivets, 2l. Straight horizontal angle-bars, 22, connect the several arch-ribs of each mold-section.

The mechanical construction for effecting the intersection and joinder of an arch rib, 19, and a straight double angle bar, 9.2, is shown in Figs. 3 and one side of each straight angle bar contacts with the other and the two are fastened together by rivets, 23; in cross-section these double horizontal bars form a T, the cross or top, 22, of which 'is the part that contacts with the cylindric shell 9A, of the mold. The vertical archribs, 19, have no notch or break at 'their intersection with. the straight horizontal bars, 22, but that part of the latter that has the rivets, 23, is cut cross-wise, and the portion between the cuts is removed and each the said vertical arch-rib, 19. The horizon Y tal bar, 22, is fastened to the vertical rib, 19, by a short arm, 26, that is integral with the bar, 22, and laps overY the base-part, 20, Aof the vertical rib, and the extremity of said short arm is bent at a right-angle, 28, and contacts with said rib, 19, and is secured thereto by a rivet, as seen in Fig. 6.

Special provision is made for moving one section of a part-cylindric mold, 14, forward after the concrete, that hasbeen supported by that mold, has hardened and set;

the means forv suchmoving comprises 'roll ers, 18, that travel on the woodstringers, 17 Eachroller, 18, turns on a journal arm, 29, which is provided at one end with-a bracketbase, 30, that is secured to the lower part of the metal shell, 24; thel journal arm projects horizontally, In Fig. 3 the part' cylindric mold-section has two rollers, 18,

one being near each end. Of course, the other half of the same mold-section, not seen in Fig. 3, also has two rollers.

By reference to Fig. 1, a rnarrow space, 31, will be seen between the top surf'ace'ofl the cross-tie, 12, and t-he'lowermost part, of the arch-rib, 34,at opposite sides of the conduit; this space indicates that the lower end of the arch-rib does not seat or rest on the cross-ties, 12. It will be understood,

therefore, that the mold-section, 14, is supported by the projecting journal arms, 29, .and rollers, 18, resting on the stringers, 17.

A wedge 39, has position on top-fof the 'cross-tie 12, andits point end in the direction of the nearest side wall is entered below the roller-stringer 17; two wedges, one

used at each opposite side, serve'to crowd the parts of the mold-section upward at the time the mold is being placed in position. When the mold is about to be removed from the concrete, the wedges serve to aidA in loosening the mold-section from the concretey by their withdrawal from below the stringer 17, which causes the stringer to tilt'down with the effect that the top of the mold-section will release from the concrete; finally on tightening the turn-buckle 33, the entire concrete.

Referring to Fig. 3, the letters A-B des ignate the two ends of a mold-section, 14,

which may be of any convenient length. The center arch-rib, 19, comprises two anglebars, but each end of this mold-section terminates with an arch-rib consisting of only one angle-bar, 34. The vend off'another angle-bar, 35, and these two angle-bars,

341-35, constituting the ends of yabutting 'mold-sections, are temporarily secured to.-

' gether by bolts, 36, each bolt being held in place by a'cotter-pin', 37, instead of screwrod, 32, see Figrl, extends cross-wise ofthe conduit or the mold, and below the side walls of the mold will loosen from thev section from A to B, as shown in Fig. 3, has Y one .double bar arch-rib, 19, between the single angle-bar ribs, 34, at each end of said section. OfA course,more than one double arch-rib may be used Vbetween the ends where the greater length of the mold-section ren-v ders more than one rib advisable.

track rails, 16, and the ends offthis rod connect with the two lower parts of theV archrib, 34. This rod Ahas a turn-buckle, 33, by means of which therodimay be lengthened` or shortened, and thereby the lower parts of the arch-rib at opposite 'sides of the conduit be: spread apart or drawn together. The crossrod, 32, is below the track-rails, and passes through notches cut'in the top surface of the Stringer, 16.v v At. the top and center ofy the mold-section, 14, is an opening that extendslongitudinally from one end t0 the other of the moldsection, and this opening is closed by a trapdoor or key, 38, see Figs. 1, 2 and 4. This opening enables the workmen who must stand within the mold, to handle thev wet mixture of concrete, and pass it from the inside of the mold through said top-opening to the outer side to form the top of the arch 11, Yat the two sides of the opening and close to the parallel stringers 43, along opposite edges' of the llongitudinal openingythusthe Y partrof the arch remaining unfilled will be only the longitudinal central top.k part,o'r'

keystone part, where said opening is. When has been dQIlGJ' the workmen inside ofthe mold will place `the trapidoor 38, in position and thereby close said opening. The workmeny willV then stand atthe forward or unconnected end of the mold-section, and pass the wet concrete'up over said' end,and place it on top ofthe closed trap-door 38, and by using av suitable implement willfpush and ram such concrete back along the upper surface of the trap-door until the space over the entire'length of said trap-door, and corres onding to a keynote, has been well filled.

- Y o permit the single arch-rib 34, shown in Fig. 1, to. slightly Atilt toward the center when preparingto remove the mold, it is preferable to remove the supplementalpiece ofribv 40,` that spans across the'` end of the top-opening that is closed by the trap-door y38; the two projecting'ends 48, of this trapdoor reston said rib-piece, and by removing the latter thesaid `trap-door itselfmay Y,

bewithd'rawn, and thereby aid in collapsing the mold. The supplemental rib piece 40,7has beveledjendssee Fig. 5, that fitcorresponding beveledtopendsof said single varch-rib Y 34, which is at the end of each mold-section.A

Said supplemental rib-piece 40, is held in its single arch-rib, 34, at

position by over-lapping plates 41, that couple the ends of the supplemental piece to the top ends of said arch-rib 34. By removing pins 42, from the over-lapping plates 41, the supplemental rib-pieces 40, may be entirely detached, and then the arch-ribs 34, at the opposite sides of the mold-section, may be loosened from the concrete wall, and slightly tilted.

The dotted curved lines in Fig. 1, are intended merely to illustrate the idea, or the direction of tilting the two opposite sides of the mold-section; in practice the extent of this inward tilting would generally be slight, sometimes as little as a half-inchenough however to release the mold from adhering to the concrete wall.

It is to be understood this description of the supplemental rib-piece, 40, and the means of its attachment at one end of a mold-section, is applicable to the opposite end of the same mold-section. Furthermore, it is to be understood such a rib-piece, 40, iskalso applicable to the next mold-sections, 35, whose ends adjoin or abut against either of the single arch-ribs, 34, of the mold-section, 14, which has just been described.

1n order to strengthen the mold-section valong the top and center where the longi` tudinal opening is, l place two parallel angle-bar stringere, 43, which extend along the top of the arch from the single arch-rib, 34, at one end of the mold-section to the the opposite end; the top ends of the middle arch-rib, 19, abut against said stringers, 43, and the downilange of said angle-bar stringer has a number of short slots, 44. Said two parallel angle-bar stringers are spaced apart from each other to form lthe top-opening, andthe two parallel down-flanges, 45, on the under side and along the two longitudinal edges of the trap-door or lrey, 38, fit between said two parallel stringers, 43, and when the trap-door is closed, pins, 46, are inserted through the holes in said down flanges, 45,

of the trap-door, and also through the slots, 44, in the stringer, 43, as shown in Fig. 4. rlhe door also has on its under side, and crosswise near each of its ends, a shorter angle-bar, 47, forming a down-fiange that extends crosswise of the door, the crossllange, 47, is far enough from the extreme end of the door for said end to form a horizontal projection, 4S, see Fig. 3. rlhe projecting end, 48, of the door rests on the top of the supplemental rib-piece, 40.

The description thus far is more particularly related to the form of mold-section,

that is part-cylindric, as shown in Fig. 1,

though much of said description is also applicable to the fully-cylindric form shown in Fig. 10. ln Fig. 10 the mold-section shown has the form of a complete cylinder; it has the same top-opening and trap-door 38, the verticalarch-ribs are the those in Fig. 10, form a complete circle, and the horizontal bars, 32, are also the same. rThe structure in Fig. 10, permits the removal of the over lapping plates, 41, of the top parts of arch-rib 19, so that both sides of the mold may tilt toward the center, for the purpose of collapsing. ln Fig. 10, two cross-rods, 49, are shown connecting with opposite sides of the arch-rib, 19; each rod has a turn-buckle, 50, that screws on the rod and enables the rod to be lengthened or shortened. To collapse, these rods must be shortened or removed.

It is to be understood that either the form of structure shown in Fig. 1, or the form shown in Fig. 10, may be used for constructing concrete conduits in a ditch which when finished is to be covered with earth.

Having thus described my invention, what I claim and desire to secure by Letters Patent is- 1. A mold-section for the formation of concrete tunnels having in combination two vertical arch-ribs 34, at each end of the mold-section; two parallel stringer bars 43, extending from the top ends of said two ribs at one end of the mold-section to the like ends of the two ribs at the other end, and said two parallel stringer bars spaced apart and forming between the two an opening along the entire top of the mold-section; a supplemental rib-piece 40, spanning across each end of said top opening and attached to the said top ends of the vertical archribs; a horizontal cylindric sheet-metal shell around said arch-ribs and at the top said shell having two longitudinal edges each of which is attached to a different one of said two stringer bars; and a trap-door having a down-flange along both longitudinal edges and fitting within said top opening and said door provided at its ends with horizontal projections which rest on said supplemental rib-pieces.

2. A mold-section for the formation of concrete tunnels having in combination a vertical arch-rib at the two opposite ends of the section; a double vertical angle-bar arch-rib 19, intermediate said ribs at the two ends; a double horizontal angle-bar 22, intersecting said vertical intermediate anor key, same, except -gle-bar arch-rib, and joined therewith by a short arm 26, that is integral with said horizontal bar and lapping over a part of said vertical arch-rib and the extremity of said short arm bent at an angle 28, and riveted to said rib, and a cylindric sheet-metal shell covering all said arch-ribs and horizontal bars.

3. A part-cylindric mold-section for the formation of concrete tunnels having in combination cross-ties supporting two stringers each adjacent to an opposite side of the mold-section and extending parallel j with said side; iwi/edges"betweenY #he cross` stringers and means on the said projectingV 10 ties and the lower surface of saldstrmg-l Yarms that rest on said strngers.

ers-'the thin edge fof each Wedge pointing In testimony Whereof'I aiX my signafure to the nearest side of the conduit and the in presence vof two Witnesses. large end of each Wedge being nearer the center of the conduit; a part-cylindric mold Y. Y, GHEENVR. ABBOTT. archedV over said erossstes andy strngers, Witnesses: A ff the lower part of both sides of said mold 'CHASL IsAAGs,

provided with arms 29, proj actingover sad- CHAs. MCGOVERN.

Copies of this p`aten't may be obtained for'ire cents each,v by addiessing t1ie.Comimiss-ioner of Patents, Weshingtong D. C. 

